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• How to read SCTE-104 messages in LIBAV [closed]

  17 août 2024, par Avnish Dass

  I am capturing a SDI signal from a Decklink card using LibAV (ffmpeg). How do I receive SCTE-104 messages embedded in the SDI ? Are these part of the Frame buf, or side_data, or some other pointer ?

  


  There seems to be no ffmpeg filter or online sample to demonstrate this.

  


• ffmpeg hangs during download on network lags

  30 juin 2016, par VladimirLenin

  ffmpeg hangs infinitely when cutting off wifi while downloading m3u8 (which goes through http actually). Same happens occasionaly when trying to download multiple files from script probably due to network lags. Tried -tiemout option but with no avail.

  ffmpeg -y -i 'http://c.brightcove.com/services/mobile/streaming/index/rendition.m3u8?assetId=5005890079001&videoId=5005830251001' -c copy -f mp4 -bsf:a aac_adtstoasc 'file:/home/serj/.mirror0/OUT_DATA2/www.watoday.com.au/title-page/Sydney v Western Bulldogs: Scoring woes could cost Swans, Dogs a flag/00001-FootyFix - Can the Doggies upset the Swans again.mp4' -timeout 1000000

• Record video with Xvfb + FFmpeg using Selenium in headless mode

  12 mars 2024, par ifdef14

  I am trying to record video using Selenium in headless mode. I am using Xvfb and FFmpeg bindings for Python. I've already tried :

  


  import subprocess
import threading
import time

from chromedriver_py import binary_path
from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from xvfbwrapper import Xvfb


def record_video(xvfb_width, xvfb_height, xvfb_screen_num):
    subprocess.call(
        [
            'ffmpeg',
            '-f',
            'x11grab',
            '-video_size',
            f'{xvfb_width}x{xvfb_height}',
            '-i',
            xvfb_screen_num,
            '-codec:v',
            'libx264',
            '-r',
            '12',
            'videos/video.mp4',
        ]
    )


with Xvfb() as xvfb:
    '''
    xvfb.xvfb_cmd[1]) returns scren num
    :217295622
    :319294854
    :
    '''
    xvfb_width, xvfb_height, xvfb_screen_num = xvfb.width, xvfb.height, xvfb.xvfb_cmd[1]
    thread = threading.Thread(target=record_video, args=(xvfb_width, xvfb_height, xvfb_screen_num))
    thread.start()
    opts = webdriver.ChromeOptions()
    opts.add_argument('--headless')
    try:
        driver = webdriver.Chrome(service=Service(executable_path=binary_path), options=opts)
    finally:
        driver.close()
        driver.quit()



  


  As much as I understand xvfb.xvfb_cmd[1] returns an information about virtual display isn't it ? When I executed this script, I got the error message :

  


  [x11grab @ 0x5e039cfe2280] Failed to query xcb pointer0.00 bitrate=N/A speed=N/A    
:1379911620: Generic error in an external library


  


  I also tried to use the following commands :

  


  xvfb-run --listen-tcp --server-num 1 --auth-file /tmp/xvfb.auth -s "-ac -screen 0 1920x1080x24" python main.py &

  


  ffmpeg -f x11grab -video_size 1920x1080 -i :1 -codec:v libx264 -r 12 videos/video.mp4

  


  In the commands above, there are used xvfb-run --server-num 1 and ffmpeg -i :1, why ?

  


  Overall, when Selenium is running in the headless mode what's going on behind the scenes ? Is it using virtual display ? If yes, how can I detect display id of this, etc. Am I on the right path ?

  


  I am not using Docker or any kind of virtualization. All kind of tests are running on my local Ubuntu machine.